Conventionally, X-ray film is examined and studied for diagnostic purposes by hanging the film manually in front of an illuminated surface in an illuminated cabinet. When a large number of films are to be examined, the films are normally hung on a plurality of transparent film frames which are positioned in front of the illuminated surface with the aid of a motor-driven conveyor mechanism.
The film frames are normally stored in magazines which may either be stationary or mobile. Moble magazines enable the frames to be conveyed between different film examining cabinets when the need arises.
Alternatively, and instead of film frame magazines, there may be used transparent plastic belts which are capable of being rolled in front of the illuminated surface in a horizontal or vertical direction.
The films are normally of a standard size, with a smallest dimension of 13.times.18 cm and a largest dimension of 35.times.43 cm. The film accommodating surface of the magazined film frames will normally be 150.times.50 cm in size.
A film frame magazine for use in an examination cabinet will normally have a capacity of 100-110 films. Some magazines, however, will accommodate 200-300 films having a maximum dimension of 35.times.43 cm.
When considering that the film frame requires a surface dimension which is about four times as large as the maximum film dimension and that about 75 films, each having a standard thickness of about 0.2 mm, can be packed depthwise within the standard or normal space between two film frames in a magazine, it will be seen that a film frame magazine demands the provision of much more space and the handling or manipulation of much heavier weight than when handling loose films. Such handling occurs, for instance, in the case of mobile routines in which the films are first hung in a cabinet for pre-examination purposes and then transported to another examination cabinet, where the films are examined and studied in greater detail.
The same also applies to the aforementioned plastic belts, which may be endless belts but which are often wound up in rolls for mobile transportation. In this respect, examination of the films can be beset with difficulties resulting from different types of operational disturbances, causing the films to be even less accessible than when stored in a frame magazine. This can have disastrous results, for instance, in catastrophic situations, or may require re-takes to be made, subjecting the patient to an increased dosage of radiation. The films are also easily deformed when rolling up the belts.
It is also known in the case of image projectors and like apparatuses to advance images sequentially from an image discharging magazine to an image examining or viewing position, and from there to an image receiving magazine.
One example of such apparatus is described and illustrated in U.S. Pat. No. 1,002,078 (Paoli). This publication describes a magic lantern in the form of a slide projector having a slide change mechanism which is effective in changing slides in a manner such that the images thereon will merge into each other without any abrupt demarcation therebetween.
Another known apparatus of the aforesaid kind is described and illustrated in U.S. Pat. No. 4,331,398 (Kawarada et al.). This publication teaches a device for transporting a plurality of slide film mounts in either direction between a pair of magazines in a slide projector with the aid of endless drive belts which extend over an open end of each magazine in close contact therewith and with stepped shoulder portions formed in the belt surface facing the open ends of the magazines.
U.S. Pat. No. 4,368,964 (Carlson) teaches a similar film-slide projector having an automatic slide changer and stationary magazine on each side of the projector, the respective slide magazines having a feed and discharge opening for slide frames which is located in the focal plane of the slide projector.
British publication 1 175 454 (Itek) describes a projector having a transparent film carrier mechanism which includes a supporting element and a positioning device for selective movement of the supporting element longitudinally or perpendicularly to the optical axis.
None of these known apparatuses, however, describes or illustrates the viewing of X-ray film, and consequently none discusses the problems particularly associated therewith. For instance, in all of the known apparatuses all films or slides to be viewed are of the same size, whereas films used for X-ray diagnosis normally vary in size, and the film sizes are considerably larger than the size of slides used in slide projectors.
Further examples of standard techniques German publications 2 039 208 (Agfa. Gevaert), 2 061 828 (Saab-Scania), 2 119 373 (Kalle) and 3 439 923 (Abels), and European publication 0 107 043 (MAP).
None of these publications, however, disclose any solution to the particular problems associated with X-ray diagnosis outlined above.